Posted
by
CowboyNeal
on Friday October 06, 2006 @06:24AM
from the gassy-mysteries dept.

dusty writes "A recent hypothesis paper entititled 'Martian CH4: Sources, Flux, and Detection' delves into the production of methane on Mars. This hypothesis compares Mars with South Africa, and draws the conclusion that the radiolysis of martian ice and water while reacting with carbon dioxide can produce enough methane to account for recently observed concentrations.
Methane is important because it is hard to explain. It has a short half-life and must be replenished frequently. As recently as 2005 the public line from NASA/JPL was that the methane could be produced by volcanism. Mars' dormant Olympus Mons is the largest volcano in the solar system but auspiciously quiet. A recent study from NOAA throws into question the whole idea stating, 'If Mauna Loa is a valid terrestrial analog, our findings suggest that volcanic activity is not a significant source of methane to the Martian atmosphere.'"

I was thinking of a way to maintain positive pressure around the various holes humans seem to carry around with their heads. I guess it would be easier to drive a space scooter if you could actually use optical receptors that aren't just registering Froolak's last meal.

The term can be applied to anything which decays with time, though radioactive decay would probably give the most attractive decay curve.

You get the same curve from anything that has a probability of decay that is independent of time.

If the probability of decay, destruction or loss for an individual atom is L per unit time, then for N atoms the rate of change of N is:

dN/dt = -L*N

and integrating gives N = No*exp(-L*t) where No is the number of atoms at some arbitrary t=0.

So for any situation where you have a constant decay probability you will get the same curve. For methane in the Martian atmosphere the rate of decay is pretty much constant due to solar ultra-violet radiation breaking up the molecules. Therefore, if there were no source the amount of methane in the atmosphere would drop exponentially.

Well, if you got that from Biology, no wonder it's a bit off! I'll give the chemist's take on it - you've got the UV bit right, but hydrogen bonds don't exist in methane, which is CH4 (CH3 is a methyl group) What it can do is break the covalent bonds between carbon and hydrogen atoms, splitting the molecule. I don't know for sure, but intuition tells me you'll get a CH3- anion, and a H+ cation. Not sure though, you might get a carbocation...

Ahh right, I knew that was a possibility from the initiation of Cl. radicals. I thought that the relative electronegativities of the halogens in CFCs was responsible for allowing homolytic fission - I presume that's something else, though, perhaps bond strength.

Once radiation breaks the (covalent) bond with one of the (four) hydrogen atoms in the methane molecule, the hydrogen won't last long. Hydrogen is light, floats to the top of the atmosphere, and gets lost into space. Water is at risk too, but it's a really tough molecule and we started with a lot of it (and it freezes and falls back down while it's still low enough in the atmosphere to have some protection from radiation).

I think the point is that the source of methane could potentially have been produced by living organisms but there is no other evidence at all of living organisms. Hence the search for what else could be the source.

Given that we know the rate of destruction of Methane on Mars we also know the rate of production, which should make it possible to estimate the mass of Methane producing bacteria, assuming that is the source.

Well, easy to guess, that those scientists already did this, compared this to data about the amount of living organisms or their remnants detected so far and decided, that it is highly improbable, that they exist at all! Thus the search for other possible sources of methane...

sorry to disappoint you: you don't have to have a lot of knowledge. Every biological production of methane (or any other substance) is in its nature a chain of chemical reactions. While the characteristics of life may differ on different planets, chemistry always stays the same- giving you at least the energy demand (or benefits) of a reaction that gives the detected amount of CH4 in an environment likes Mars' atmosphere from the substances there.
To make an estimation about how much living mass would be a

I think the point is that the source of methane could potentially have been produced by living organisms but there is no other evidence at all of living organisms. Hence the search for what else could be the source.

Given that the ONLY experiment ever designed to specifically test for life on Mars had a POSITIVE RESULT, I think it's highly misleading to say that there is NO evidence for living organisms on Mars. Remember, just because there is evidence for something doesn't mean that something is true. It

There are a number of Mars lander missions planned by NASA and ESA that will try to answer that very question. The new rovers will drill up to 100 cm under the surface and a new generation of chemical analyzers will look at the chemical results from that deep in the soil. It's likely that small microbes could live in the Martian soil using small amounts of water moisture trapped in the soil.

No, it's not likely. Everything that we've come to learn about Martian regolith is that it's highly oxidative -- peroxides, superoxides, etc. Then factor in the problems we've known for a long time -- radiation, temperatures, lack of liquids, etc.

If there's any life there, it must be extremely different from life on Earth to be able to withstand the oxidative environment. On Earth, Martian regolith would be a disinfectant.

Besides, volcanism and this new theory aren't the only viable ones for methane production. Serpentization of olivine will do the trick as well. That is to say, if anywhere on the planet there is subsurface water saturated with CO2 in ever-common olivine-rich rock, it will produce methane.

In truth, there has never been a test on a Martian lander designed to either confirm or identify the nature of this hypothetical strong oxidant. While there are theories that suggest that UV light should create such oxidants, the presence of a higly oxidant Martian surface has never been confirmed by experiment. Rather, it has been invoked as an EXPLANATION why certain other results, such a the Viking LRE, must be faulty.

To date, no subsequent Mars probe has produced data that points to a strong global surface oxidation beyond the usual culprits of H20 and CO2 (which account for the rust).

Not only UV, but also dust devils. Experiments on simulated dust devils show that they produce about 200 times more H2O2 than UV does.H2O2 *has* been detected on Mars. In 2003, the IR TEXES spectrometer team detected 20-50 ppb of H2O2 in the atmosphere. The James Clerk Maxwell Telescope confirmed this. Since it doesn't last long in the atmosphere, this means that it's constantly being produced. H2O2 bound to dust particles would end up in the soil, so this observation is consistant with theory.

The problem is that when Viking did its soil sampling it did it only on the very surface of the topsoil, which may not have enough water and is too exposed to UV rays from the Sun to support even microbes. This is why I suggest drilling down 100 cm into the soil--at that point, there may be still enough water trapped in the soil to support primitive microbial lifeforms.

Nope. Its "the most powerful". While they might cover the same surface area, Olympus Mons stands much higher.

True, Olympus Mons [solarviews.com] is absolutely huge. The summit is at 27 kilometres above the mean surface level on Mars and it covers a surface area the size of Arizona. It would be fantastic to be able to stand on that summit and enjoy the view.

just turning C02 + H2O + energy -> CH4 +...would be seriously dumb as CH4 is a much more potent greenhouse gas than C02, and stockpiling it would harder than just stockpiling the CO2 in the first place.

and turning C02 + H20 + energy -> CH4 then burning the CH4 to get C02 + energy is just a nice way of wasting energy.

You're not talking about a power source, just an expensive and dangerous power transmission medium.

And finaly, what on earth do you mean by fragile biological processes? Artificial processes are way more fragile than biological ones.

You can't power a rocket to take you back home with solar panels. You might be able to do so with stuff like methane. I think that this is the basic idea. I doubt that they need methane to power equipement destined to stay on the planet.

and turning C02 + H20 + energy -> CH4 then burning the CH4 to get C02 + energy is just a nice way of wasting energy.

Well, burning methane would produce CO2 + H20 and energy. It's a nice way of wasting energy if you have to produce the methane, but it's already there. So, it's a good source of energy (which could be stored or used) but also a good source of water (which is kind of a necessity for terraforming and/or human survival).

So, if you ask me, I think the large, renewable supply of methane on mar

You're not talking about a power source, just an expensive and dangerous power transmission medium.Dangerous? I think it's under control. We use this all the time. What about those natural gas pipes everywhere?

Uhm. Since always? Science is the whole idea of making a (thought out or not) statement, and then setting about disproving it. If you fail to disprove it, you end up with the 'last option is that it's true' idea.

I agree totally and welcome our new bacterial overlords.Science, particularly in the US, seems to be slipping back into its old habits. Dogma reigns supreme and dissident voices are quashed without cause or concern simply for going against the norm.

A friend of mine used to argue that science was no different from religion, and scientists a new breed of priest. I hated his argument, but lately I have had to question how valid that may be.

The question to ask then is, why would life on Mars recieve such scathi

> "Who benefits from from perpetuating the belief that there can be no life on Mars?"

The most logical answer is just "common sense." It's been universally accepted that Mars is a barren planet for hundreds of years (mice in telescopes and canals aside). That builds a lot of inertia to overcome by anyone that wants to come along and change that belief.

The other possibility is a roadblock that The Mars Society and The Mars Underground ran into a couple of years back. Their goal is to get NASA to Mars an

Science isn't about believing anything is possible until proved otherwise. I think many scientists would agree that it's possible there is or was life on Mars. But life evolving independently anywhere other than Earth would be a major breakthrough for science, so they want to be very careful about claiming it until it is really, unquestionably proved. IMO this is just good science.

The problem is that "facts" are slippery creatures. People lie. Instruments are faulty. Methods are applied incorrectly. Relationships between variables are misunderstood. There are all sorts of reasons why what we think of as factual may be incorrect. To combat this science requires that experiments be repeatable under controlled conditions. Given enough trials, we tend to believe that the facts, at least, are correct. This establishes "dogma", if you like, but I would say it establishes a baseline of pret

Surely if one applies occams razor to the question, we must believe strongly in the possibility that Mars does indeed have the capability of supporting some forms of primitive life.

Correct me if I'm wrong, but I think this is a misuse of Occam's Razor. The principle basically says that the solution that requires the fewest number of variables is most likely to be correct. So in this case, the existance of life on mars is a big "extra", if the presence of methane can be explained without it.

The question to ask then is, why would life on Mars receive such scathing denials from the scientific community?

What do you mean? They have sent lots of missions to Mars, spent billions of dollars doing that, and still try again to find any sign of life.

If scientists were so interested in denying the existence of life in Mars they wouldn't have had any need to send other spacecraft after the Viking missions in 1976. But they still keep trying, even if the data seems to indicate that Mars is lifeless and ha

"'If Mauna Loa is a valid terrestrial analog, our findings suggest that volcanic activity is not a significant source of methane to the Martian atmosphere.'"

Man, I wish more of our scientific quotes sounded like this one. It lays it out straight and simple. Here is our source of info: analogy with Mauna Loa. Here is our assumption: we can project info from it onto Olympus Mons. Here is our conclusion: there is something else other than volcanic activity producing methane on Mars. I like how all that info was neatly packaged into a simple sentence. I also like how he admits the assumption... if. The thing that comes to mind are all the dinosaur shows explaining their day to day lives, zodiac signs and favorite take-out places.

Didn't Thomas Gold postulate that we'd find lots of methane on Mars? He had many intriguing theories on "deep life" - and recent evidence of "replenishment" of petroleum reserves, IIRC, while puzzling to geologists following the standard theories, would not have been a mystery to him.

Did Gold predict methane on Mars? Most likely. He's predicted it just about everywhere else. Mostly, he's been wrong. One can make a pretty good case that if you shoot enough arrows you're bound to hit something occasionally.

Didn't Thomas Gold postulate that we'd find lots of methane on Mars? He had many intriguing theories on "deep life" - and recent evidence of "replenishment" of petroleum reserves, IIRC, while puzzling to geologists following the standard theories, would not have been a mystery to him.

Dr. Gold was also convinced that the Moon was covered in dust many meters deep - after the Surveyor landings showed that to be incorrect, he changed his belief to 'the moon is covered in dust with a crust just thick enough to